1. (non-transitive) to decelerate.
2. (transitive) to cause a given object to decelerate.
Note: This word is NOT a noun, therefore anyone who descends to the level of naming an unfortunate person with mental disabilities (actually known as a retardee, a subject of mental retardation) a "retard" (with a mysterious emphasis on the first syllable) can be classified as illiterate, and can be ignored as a result. These people should be ignored anyway as they obviously have no sense of decency or sensitivity. This also applies to people who call non-retardees, "retards", implying that to be a "retard" indicates a status worthy of ridicule.
1. At that point the car had, for some reason, begun to retard.
2. At that point the driver had, for some reason, begun to retard his car.
by XXXXXX Jan 11, 2006
"I did. What's up with that retard?"
"Probably a retarded virgin who thought this was Webster's"
"Retard. Can you believe anyone voted that definition up?"
"I know, what a bunch of retards."